<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style>
        
    </style>
</head>
<body>
    
</body>
<script>
    
    console.log(typeof "hello"); //string
    console.log(typeof "true"); //string
    console.log(typeof "123123"); //string
    console.log(typeof "{}"); //string
    console.log(typeof "function(){}"); //string
    console.log(typeof "undefined"); //string

    console.log(typeof 123); //number
    console.log(typeof -123); //number
    console.log(typeof -123.345); //number
    console.log(typeof NaN); //number

    console.log(typeof true);//boolean
    console.log(typeof false);//boolean
    
    console.log(typeof undefined); //undefined
    
    console.log(typeof function(){}); //function
    
    console.log(typeof {}); //object
    console.log(typeof []); //object
    
    console.log(typeof null); //object


    // 注意点：（面试题）
    console.log(typeof typeof true); //string
    // typeof的检测结果以什么类型存在？字符
    // 多个typeof检测结果必然是string

</script>
</html>